Polyamide resins have excellent resistance to organic solvents, such as gasoline, and further have high fluidity upon melting so that they exhibit excellent moldability, and have excellent thermal properties and excellent mechanical properties. Therefore, the polyamide resins have been widely used as automotive exterior materials and engine room internal parts.
Fuel parts, such as a fuel cap, which are to be in contact with both a fuel and a part of a human body have a danger that electrostatic discharge generated when, for example, opening or closing a cap causes ignition. For this reason, for the purpose of suppressing the occurrence of discharge, a composition containing, for example, carbon black having electrical conductivity has been used in the fuel parts.
On the other hand, printing is often made on fuel parts, and the fuel parts are required to be suitable for laser marking which is excellent in respect of the cost and productivity. For achieving excellent laser marking property and excellent impact resistance, Japanese Unexamined Patent Publication No. 2011-32320 has proposed a composition comprising carbon black, a carbon fiber, aramid, and a metal-plated organic fiber masterbatch. Further, Japanese Patent No. 4889987 has proposed a polyamide resin composition comprising an ethylene-α-olefin copolymer, modified high-density polyethylene, and carbon black.